Why does my Tic Tac Toe logic have errors sometimes?

Question

Im new to posting questions here so let me know if ive done something wrong. So this program works fine 90% of the time as seen here.

But then the logic is off sometimes as seen here. Ive looked through my code for a while so ive finally given in and ask for help! My logic() function seems to be accurate. Ive matched all possible routes to win; rows, columns and diagonals. For some reason if the top row is -> 'X' | 'O' | 'X' -> it declares player one (x) to be the winner. Any ideas?

 #include <iostream>
    #include <iomanip>

using namespace std;

void drawBoard();
char board[3][3] = {'1','2','3','4','5','6','7','8','9'};   // 3x3 board
char player = 'X';
void game();
void toggle();
char logic();
void winner();
int main()
{
    drawBoard();
    while(1){
        game();
        drawBoard();
        toggle();
        if(logic() == 'X')
            cout << "Player 1 (X) Wins!" << endl;
        else if(logic() == 'O')
            cout << "Player 2 (O) Wins!" << endl;

    }

    return 0;
}

void drawBoard(){

    system("cls");
    cout << setw(35) << "Tic Tac Toe V 2.0! " << endl << endl;
    cout << setw(21) << board[0][0] << " | " << board[0][1] << " | " << board[0][2] << endl;
    cout << setw(30) << " --------- " << endl;
    cout << setw(21) << board[1][0] << " | " << board[1][1] << " | " << board[1][2] << endl;
    cout << setw(30) << " --------- " << endl;
    cout << setw(21) << board[2][0] << " | " << board[2][1] << " | " << board[2][2] << endl;

}

void game(){

    int input;

    cout << "Make your move..." << endl;
    cin >> input;

    if(input == 1)
        board[0][0] = player;
    else if(input == 2)
        board[0][1] = player;
    else if(input == 3)
        board[0][2] = player;
    else if(input == 4)
        board[1][0] = player;
    else if(input == 5)
        board[1][1] = player;
    else if(input == 6)
        board[1][2] = player;
    else if(input == 7)
        board[2][0] = player;
    else if(input == 8)
        board[2][1] = player;
    else if(input == 9)
        board[2][2] = player;


}

void toggle(){

    if(player == 'X')
        player = 'O';
    else
        player = 'X';

}


char logic(){
// Player 1
    /// Across
    if(board[0][0] == 'X' && board[0][1] == 'X' && board[0][2] == 'X')
        return 'X';
    else if(board[1][0] == 'X' && board[1][1] == 'X' && board[1][2] == 'X')
        return 'X';
    else if(board[2][0] == 'X' && board[2][1] == 'X' && board[2][2] == 'X')
        return 'X';
    /// Columns
    else if(board[0][0] == 'X' && board[1][0] == 'X' && board[2][0] == 'X')
        return 'X';
    else if(board[0][1] == 'X' && board[1][1] == 'X' && board[2][1] == 'X')
        return 'X';
    else if(board[0][2] == 'X' && board[1][2] == 'X' && board[2][2] == 'X')
        return 'X';
    /// Diagonals
    else if(board[0][0] == 'X' && board[1][1] == 'X' && board[2][2] == 'X')
        return 'X';
    else if(board[0][2] == 'X' && board[1][1] == 'X' && board[2][0] == 'X')
        return 'X';

// Player 2
    /// Across
    if(board[0][0] == 'O' && board[0][1] == 'O' && board[0][2] == 'O')
        return 'O';
    else if(board[1][0] == 'O' && board[1][1] == 'O' && board[1][2] == 'O')
        return 'O';
    else if(board[2][0] == 'O' && board[2][1] == 'O' && board[2][2] == 'O')
        return 'O';
    /// Columns
    else if(board[0][0] == 'O' && board[1][0] == 'O' && board[2][0] == 'O')
        return 'O';
    else if(board[0][1] == 'O' && board[1][1] == 'O' && board[2][1] == 'O')
        return 'O';
    else if(board[0][2] == 'O' && board[1][2] == 'O' && board[2][2] == 'O')
        return 'O';
    /// Diagonals
    else if(board[0][0] == 'O' && board[1][1] == 'O' && board[2][2] == 'O')
        return 'O';
    else if(board[0][2] == 'O' && board[1][1] == 'O' && board[2][0] == 'O')
        return 'O';
}

Answer 1

In the function logic(), you are missing a return statement, meaning that if none of the conditions are satisficed, the function will just return anything that could have been in that register. I found that if you add a return 0; to the end of the function, you don't get that behavior.